_StringReverse revamp

SxyfrG · April 24, 2008

This is my alternate _StringReverse function (with added progress bar if you want).

I searched the forums to see if anyone has posted something like this and i didn't see any posts so ... yeah, enjoy

;String = String you wish to reverse
;prog   = True: Show progress, False: do not show progress
Func __StringReverse($String,$prog=False)
    Local $Split, $ReturnString, $Progress, $Percent
    
    $Split = StringSplit ( $String , "" )
    If $Prog = 1 Or $Prog = True Then
        $Progress = ProgressOn ( "__StringReverse" , "Reversing String..." , "" , Default , Default , 16  )
    EndIf
    
    $Percent = 0
    For $i = $Split[0] To 1 Step -1
        $Percent += 1
        $ReturnString &= $Split[$i]
        If $Prog = True Then
            ProgressSet ( 100-Abs(($Percent/$Split[0])*100) , "" )
        EndIf
    Next

        If $Prog = True Then ProgressOff()
    
    Return $ReturnString
EndFunc

Tested times on my computer:

100,000 character length string

_StringReverse = 15 seconds

__StringReverse = 1.5 seconds

1,000,000 character length string

_StringReverse = Took too long, i got bored (approx 15*10 = 150 seconds or 2 minutes and 30 seconds)

__StringReverse = 11.2 seconds

(my computer is fairly fast: 2.4ghz Duo-core processor, 3gb RAM etc)

Just thought i'd share this

Edited April 24, 2008 by SxyfrG

TomZ · April 24, 2008

You've two flaws in your code. At first, you don't call progressoff. The second flaw is a bit 'bigger', it makes the program loose speed:

Compare this:

$timer = TimerInit()

$true = True

For $n = 1 to 10000000

If $true Then

Do_Something()

Endif

Do_Something_Else()

To this:

$timer = TimerInit()

$true = True

If $true Then

For $n = 1 to 10000000

Do_Something()

Do_Something_Else()

For $n = 1 to 10000000

Do_Something_Else()

ConsoleWrite(TimerDiff($timer))

Edited April 24, 2008 by TomZ

SxyfrG · April 24, 2008

I fixed the progressoff() bug just a second before you posted, but i don't get what you're saying about the program losing speed, with and without the extra progress bar option, the time difference was negligible (if that's what you're talking about).

Edited April 24, 2008 by SxyfrG

SxyfrG · April 24, 2008

You've two flaws in your code. At first, you don't call progressoff. The second flaw is a bit 'bigger', it makes the program loose speed:
Compare this:
$timer = TimerInit()
$true = True
For $n = 1 to 10000000
If $true Then
Do_Something()
Endif
Do_Something_Else()
Next
ConsoleWrite(TimerDiff($timer))
To this:
$timer = TimerInit()
$true = True
If $true Then
For $n = 1 to 10000000
Do_Something()
Do_Something_Else()
Next
Else
For $n = 1 to 10000000
Do_Something_Else()
Next
EndIf
ConsoleWrite(TimerDiff($timer))

Actually i do get what you're talking about.

I re-tested the function and cut the time by more than half by commenting out the progress bar option.

Siao · April 24, 2008

Actually i do get what you're talking about.

I re-tested the function and cut the time by more than half by commenting out the progress bar option.

You can split the code if you want to leave the progress functionality in:

Func __StringReverse2($String,$fProg=False)
    Local $Split, $ReturnString, $Progress, $Percent
    
    $Split = StringSplit($String , "")
    If $fProg Then
        $Progress = ProgressOn ( "__StringReverse" , "Reversing String..." , "" , Default , Default , 16  )
        $Percent = 0
        For $i = $Split[0] To 1 Step -1
            $Percent += 1
            $ReturnString &= $Split[$i]
            ProgressSet(100-Abs(($Percent/$Split[0])*100) , "")
        Next
        ProgressOff()       
    Else
        For $i = $Split[0] To 1 Step -1
            $ReturnString &= $Split[$i]
        Next        
    EndIf
    
    Return $ReturnString
EndFunc

It's a very basic optimizing technique.

Btw, I guess this just reinforces something I noticed earlier, ~~that AutoIt string functions take advantage of multicores.~~ (scratch that, it's mainly just because _StringReverse() is horribly outdated, not even using "&=" oparator for concatenation...)

Because on my old P4 the difference between the versions is even more severe:

"official" _StringReverse (uses StringMid approach) takes friggin 63+ secs for 100k char string

your first non-optimal version takes 1.8 secs.

the one above takes 1.1 secs.

Overall, I say, good job on this one. Too bad the devs are perfectly happy with old and slow functions being included in AutoIt core package even when presented an alternative. And it's not a critical or oft used UDF. Honestly I don't know why these functions are part of core package to begin with, if any coder should be able to achieve the same with 1 For...Next loop in 3-4 lines.

Edited April 24, 2008 by Siao

crashdemons · April 24, 2008

Okay - it runs fast on a single string.

BUT - does it run fast on multiple small strings back-to-back?

I have a feeling creating an array with StringSplit 8000 times might cause your function do lose this race.

It seems, the bigger the test-string, the more advantage your function has

- but, the more times back-to-back it's ran, the more advantage the original UDF function has

Using the code below, I got:

"

_StringReverse Took 2894.73326917248ms

__StringReverse Took 3022.60566636262ms

__StringReverse2 Took 2255.45816577247ms

"

EDIT: Re-ran with the StringReverse2 posted.

$str="ab"
$times=8000
#include <String.au3>
;-- Put your __StringReverse declaration here --;
;-- Put your __StringReverse2 declaration here --;
$t=TimerInit()
For $i=1 To $times
    _StringReverse($str)
Next
ConsoleWrite("_StringReverse Took "&TimerDiff($t)&"ms"&@CRLF)
$t=TimerInit()
For $i=1 To $times
    __StringReverse($str)
Next
ConsoleWrite("__StringReverse Took "&TimerDiff($t)&"ms"&@CRLF)
$t=TimerInit()
For $i=1 To $times
    __StringReverse2($str)
Next
ConsoleWrite("__StringReverse2 Took "&TimerDiff($t)&"ms"&@CRLF)

Edited April 24, 2008 by crashdemons

crashdemons · April 24, 2008

OR, how about this, Complete with "_TestFuncSpeed"

Testing Processing Speeds:
"_StringReverse($str)" Took 2328.59902585384ms
"__StringReverse($str)" Took 770.042840640361ms
"__StringReverse2($str)" Took 520.423685133166ms
Testing Initialization Speeds:
"_StringReverse($str)" Took 2303.33547978863ms
"__StringReverse($str)" Took 3401.60718750568ms
"__StringReverse2($str)" Took 2670.47068831374ms

#include <String.au3>
;-- Put your __StringReverse  declaration here --;
;-- Put your __StringReverse2 declaration here --;


Func _TestFuncSpeed($ExecuteString,$TestLoop=1,$OutputResults=True)
    $t=TimerInit()
    For $i=1 To $TestLoop
        Execute($ExecuteString)
    Next
    $result=TimerDiff($t)
    If $OutputResults Then  ConsoleWrite('"'&$ExecuteString&'" Took '&$result&'ms'&@CRLF)
    Return $result
EndFunc

;Testing here
$str=_StringRepeat('ab',8000)
$times=1
ConsoleWrite("Testing Processing Speeds:"&@CRLF)
_TestFuncSpeed("_StringReverse($str)",$times)
_TestFuncSpeed("__StringReverse($str)",$times)
_TestFuncSpeed("__StringReverse2($str)",$times)

$str='ab'
$times=8000
ConsoleWrite("Testing Initialization Speeds:"&@CRLF)
_TestFuncSpeed("_StringReverse($str)",$times)
_TestFuncSpeed("__StringReverse($str)",$times)
_TestFuncSpeed("__StringReverse2($str)",$times)

Edited April 24, 2008 by crashdemons

Siao · April 24, 2008

Hm, time check this too

Func _StringReverseCRT($sString)
    Local $tBuff
    If StringLen($sString) >= 1 Then
        $tBuff = DllStructCreate("wchar[" & StringLen($sString)+1 & "]")
        DllStructSetData($tBuff, 1, $sString)
        DllCall("msvcrt.dll","ptr:cdecl","_wcsrev", "ptr",DllStructGetPtr($tBuff))
        If @error Then Return SetError(@error,0,"")
        Return DllStructGetData($tBuff, 1)  
    Else
        Return SetError(1,0,"")
    EndIf   
EndFunc

crashdemons · April 24, 2008

Hm, time check this too

Showing Results

Testing Processing Speeds:
"_StringReverse($str)" Took 2684.66997900571ms
"__StringReverse($str)" Took 832.423115228332ms
"__StringReverse2($str)" Took 1012.59461747233ms
"_StringReverseCRT($str)" Took 1.72172720275901ms
Testing Initialization Speeds:
"_StringReverse($str)" Took 2913.20461120059ms
"__StringReverse($str)" Took 3826.90509548001ms
"__StringReverse2($str)" Took 2789.22293196482ms
"_StringReverseCRT($str)" Took 4622.43609173792ms

Back-to-Back speeds weren't great but - holy - the processing speed on a single long string was F.A.S.T.

SxyfrG · April 24, 2008

My time results ...

Testing Processing Speeds: (1)
"_StringReverse($str)" Took 334.153083539561ms
"__StringReverse($str)" Took 89.0102095792947ms
"__StringReverse2($str)" Took 54.7416769780711ms
"__StringReverseCRT($str)" Took 0.0405650649618478ms
Testing Initialization Speeds: (80000)
"_StringReverse($str)" Took 2787.18255825943ms
"__StringReverse($str)" Took 3428.77028124356ms
"__StringReverse2($str)" Took 2773.16764710937ms
"__StringReverseCRT($str)" Took 574.129117687496ms

Great work Siao

Edited April 24, 2008 by SxyfrG

Sign In

_StringReverse revamp

Recommended Posts

SxyfrG

TomZ

SxyfrG

SxyfrG

Siao

crashdemons

crashdemons

Siao

crashdemons

SxyfrG

Create an account or sign in to comment

Create an account

Sign in

Recently Browsing 0 members

Browse

AutoIt Resources

Release

Beta